In a lane departure prevention system for preventing a vehicle from departing from a lane of travel, braking power is selectively applied to the wheels to impart a yaw moment to the vehicle.
In such a system the driver may be discomforted, since the yaw moment is always generated by the use of braking power selectively applied to the wheels, thereby decelerating the vehicle.
On the other hand, when the vehicle is tending to depart from the lane of travel, the yaw moment may be imparted to the vehicle by appropriate steering, but the desired yaw moment may not be imparted to the vehicle by steering only, depending upon certain conditions of the vehicle with respect to the lane of travel, such as yaw angle or the like.
The present lane departure prevention system can optimally prevent lane departure in accordance with the traveling conditions of the vehicle without discomfort to the driver.
The present lane departure prevention system comprises a position detector means for detecting positional information of a vehicle with respect to a lane of travel; a determining unit for comparing the positional information with a first threshold value indicating a predetermined positional relationship with respect to the lane of travel, and for determining impending departure of the vehicle from the lane of travel on the basis of the result of the comparison; and a yaw moment applying unit for applying a yaw moment to the vehicle and switching between a first process of applying yaw moment to the vehicle only by steering its wheels and a second process of applying the yaw moment to the vehicle by steering its wheels and applying driving power to the wheels, on the basis of a traveling condition of the vehicle, when the determining unit determines that the vehicle is tending to depart from the lane of travel.
In the present lane departure prevention system it is possible optimally to prevent the vehicle from departing from the lane of travel in accordance with the traveling conditions of the vehicle without discomforting the driver, since a process for imparting the yaw moment to the vehicle only by steering its wheels and a process for imparting the yaw moment to the vehicle by steering the wheels and applying driving power to the wheels are selectively switched on the basis of the traveling conditions of the vehicle when it is determined whether the vehicle is tending to depart from the lane of travel,